JP2008180986A - Display device and theft prevention method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display system in which the work of a user and the trouble of paying attention, for theft prevention are reduced. <P>SOLUTION: A display device 2 previously stores the set values of a projection distance and an inclination, measures the projection distance and the inclination, when a power is supplied, and allows the user to use the display device 2 and starts projection to a projection surface 1, when the measurement values of the projection distance and the inclination coincide with the set values. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a display device having an anti-theft function.

  An anti-theft function is mounted on a display device that projects an image. The anti-theft function is a function for preventing an action of stealing a display device. An example is a password theft prevention function. A display device having a password theft prevention function stores a password set by the user in advance, and allows the user to input the password when the power is turned on. When a password is input from the user, the display device determines whether or not the input password matches the stored password. If the password matches, the display device permits the user to use the password.

  Another example is a theft prevention function using an authentication key. The user sets authentication data in advance in both an authentication key, for example, an authentication USB (Universal Serial Bus) memory and a display device. The display device performs authentication by accessing the USB memory when the power is turned on. When the display device is powered on, an authentication USB memory is inserted into the display device, and if the authentication by the authentication data is successful, the display device permits the user to use it.

  However, in the display device having the antitheft function described above, it is necessary to input a password or insert an authentication key each time the power is turned on. In addition, when other users use the display device, it is necessary for a user who knows the password to tell the other user the password or to input the password himself. Further, in the case of a display device using an authentication key, when the authentication key is lent to another user, the key must be collected after use.

With respect to the problem of forcing such a user to perform troublesome work, Patent Document 1 proposes a display device that can prevent theft without inputting a password or inserting an authentication key. The display device proposed in Patent Document 1 has a security switch, and switches to the anti-theft mode when the security switch is pressed. The anti-theft mode is a mode in which all functions are restricted to a stopped state when the user lifts them. If the user lifts after switching to the anti-theft mode, the display device detects that it has been lifted, constrains all functions to a stopped state, and informs that effect by voice. As a result, a person who tries to steal the display device recognizes that the display device cannot be used and abandons the stealing of the display device.
JP 2006-243001 A

  However, since the display device proposed in Patent Document 1 switches to the anti-theft mode by pressing the security switch, when the user uses the display device, the anti-theft mode must be released by pressing the security switch again. I had to. If the user accidentally lifts the display device without canceling the anti-theft mode, the display device may be restrained in a stopped state, and it is necessary for the user to take troublesome care during use.

  An object of the present invention is to provide a display system in which inconvenience associated with theft prevention is reduced and convenience is increased.

In order to achieve the above object, the display device of the present invention provides:
A display device that projects an image on a projection surface,
A storage unit for storing the first distance;
When the power is turned on, a distance sensor unit that measures the distance to the projection surface;
A determination unit that determines whether or not a distance measured by the distance sensor unit matches the first distance;
If the result of the determination by the determination unit indicates that they match, the image can be projected onto the projection surface, and if it does not match, the image is projected onto the projection surface. An image projection unit that cannot be adjusted.

  In general, it is assumed that display devices that project an image on a projection surface are used at the same distance or the same inclination. If the display devices are used at the same distance or the same inclination, the display device is Allow use. When a display device is stolen, it is difficult to assume that a display device that is stolen at the same distance as the user uses or at the same inclination as the user uses is the same as the distance used by the user. If the display device is not used at the same distance or the same tilt as that used by the user, the display device does not permit the use.

  According to the present invention, the user can use the display device without performing an operation such as entering a password or inserting a key, and even without releasing the anti-theft mode before paying attention or paying attention to it. Since the display device can be used by returning to the original installation state, the trouble of the user's work and attention associated with theft prevention is reduced.

  According to the present invention, the user's work and the troublesomeness of paying attention accompanying theft prevention are reduced.

  Embodiments for carrying out the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing an installation state of a display system having an antitheft function in the present embodiment. The display system includes a screen 1 and a display device 2.

  The screen 1 is a projection surface that displays an image projected from the display device 2. In this example, the dedicated screen 1 is used as the projection surface, but a wall or the like may be used instead.

  The display device 2 is a device that projects an image on the screen 1. The display device 2 is not subject to a predetermined distance from the front surface of the display device 2 to the screen 1 existing in the front (hereinafter referred to as “projection distance”) and a predetermined inclination of the device itself due to the anti-theft function. Prohibits image projection. This makes it difficult to use the display device 2 even if it is stolen, so stealing itself becomes useless. As a result, it becomes difficult to cause the display device 2 to steal.

  In order to prevent theft, the display device 2 includes an initial setting process for storing a projection distance and an inclination used for determining whether to permit use, and a permission determination process for determining whether to permit use. Two processes are performed. First, the initial setting of the display device 2 will be described. When the power is turned on, the display device 2 measures the projection distance and the inclination. If the display device 2 does not store the projection distance and tilt, the display device 2 stores the measured projection distance and tilt internally.

  Next, permission / rejection determination of the display device 2 will be described. When the power is turned on again after storing the projection distance and inclination, the display device 2 measures the projection distance and inclination. The display device 2 determines whether or not the measured projection distance matches the stored projection distance, and if they match, subsequently determines whether or not the measured tilt matches the stored tilt. To do. If they match as a result of the determination, the display device 2 permits the use to the user and enables the projection of the image onto the screen 1. If either one does not match, the display device 2 does not project an image onto the screen 1.

  FIG. 2 is a block diagram showing a configuration of the display device 2 in the present embodiment. The display device 2 includes a distance sensor unit 20, an acceleration sensor unit 21, a storage unit 22, a determination unit 23, and an image projection unit 24. FIG. 3 is a schematic diagram showing the inclination of the display device 2 in the present embodiment. With reference to FIG. 2, the structure of the display apparatus 2 in this embodiment is demonstrated.

  When the power of the display device 2 is turned on, the distance sensor unit 20 emits pulsed light forward and receives reflected light of the irradiated pulsed light. At that time, the distance sensor unit 20 measures the delay time of the pulsed light from irradiation to light reception, and measures the distance by converting the measured time into the distance. For example, since the speed of light is 300,000 km per second, if the delay time of pulsed light is 10 nanoseconds, the optical path distance is 3 m. Since the time from the irradiation of the pulsed light to the reception thereof is a reciprocal time, the distance between the distance sensor unit 20 and, for example, the screen 1 is half of 1.5 m. In this example, pulsed light is used to measure the distance, but infrared light, ultrasonic waves, or the like may be used.

  When the power of the display device 2 is turned on, the acceleration sensor unit 21 detects the value of a decomposition component of static gravity acceleration such as the gravity acceleration of the earth and measures the inclination. For example, as shown in FIG. 3, the acceleration sensor unit 21 detects the values of three-axis decomposition components in two horizontal directions (X axis and Y axis) orthogonal to each other and in the vertical direction (Z axis). For example, the X-axis is an axis in the optical axis direction of the display device 2, and the Y-axis is parallel to the installation surface at a predetermined position (hereinafter referred to as “origin”) on the X-axis in the acceleration sensor unit 21. The Z axis is an axis perpendicular to the X axis and the Y axis at the origin.

  For example, as shown in FIG. 3, when the display device 2 is installed at an angle of θ in the upward direction, the relationship between θ and the decomposition component of the triaxial acceleration is αX = 9.81 × sin θ, αY = 0 and αZ = 9.81 × cos θ. In this state, the angle formed by the Z axis and the vertical direction is θ. In this case, in order to measure the inclination, αX = 9.81 × sin θ is θ = asin (αX ÷ 9.81), or αZ = 9.81 × cos θ is θ = acos (αZ ÷ 9.81). And the value of the acceleration decomposition component detected by the acceleration sensor unit 21 may be substituted into the converted θ = asin (αX ÷ 9.81) or θ = acos (αZ ÷ 9.81).

  Assuming that the acceleration αX detected by the acceleration sensor unit 21 in the X-axis direction is 4.9, θ is calculated as 30 degrees from θ = asin (4.9 ÷ 9.81), so the inclination is 30 upward. Degree. In this example, an acceleration sensor is used to measure the angle, but any device capable of measuring the angle may be used.

  The storage unit 22 stores the projection distance measured by the distance sensor unit 20 and the inclination measured by the acceleration sensor unit 21 as the initial setting values if the projection distance and the tilt initial setting values are not stored when the power is turned on. To do.

  Further, the projection distance and inclination once recorded inside can be changed according to a request from the user. The condition for the change is that a plurality of input keys provided in the apparatus main body are pressed in a predetermined order and number of times, and the storage unit 22 that has confirmed such input contents erases the current stored contents. It is good as well. As a result, the projection distance and inclination when the power is subsequently turned on are newly set.

  When the initial setting value is stored in the storage unit 22, the determination unit 23 temporarily turns off the power of the display device 2. In addition, if the determination unit 23 stores the projection distance and inclination in the storage unit 22 when the display device 2 is turned on, the determination unit 23 stores the projection distance and the power stored in the storage unit 22. It is determined whether or not the projection distance measured by the distance sensor unit 20 matches, and if they match, the inclination stored in the storage unit 22 and the inclination measured by the angle sensor unit 21 when the power is turned on are subsequently determined. Are determined to match.

  If the determination unit 23 matches the inclination, the image projection unit 24 permits the use of the display device 2 and starts projecting an image onto the screen 1. The determination unit 23 selects one of the projection distance and the inclination. Otherwise, the image is not projected onto the screen 1.

  FIG. 4 is a flowchart showing the operation of the display device 2 having the anti-theft function in the present embodiment. The process of the display device 2 described here includes two processes: an initial setting process for storing the projection distance and inclination, and a permission determination process for determining whether to permit use.

  First, the initial setting process will be described. When the power of the display device 2 is turned on, the distance sensor unit 20 measures the projection distance from the screen 1 (step 100). Next, the storage unit 22 stores the projection distance measured by the distance sensor unit 20 (step 101). Subsequently, the angle sensor unit 21 measures the inclination (step 102). Next, the storage unit 22 records the inclination measured by the angle sensor unit 21 (step 103). And if inclination is memorize | stored in the memory | storage part 22, the determination part 23 will once cut | disconnect the power supply of the display apparatus 2 (step 104).

  Next, the permission / rejection determination process will be described. When the display device 2 is turned on, the determination unit 23 reads the projection distance and inclination stored in the storage unit 22 (step 105). Next, the distance sensor unit 20 measures the projection distance (step 106). The determination unit 23 compares the projection distance measured by the distance sensor unit 20 with the projection distance read from the storage unit 22 (step 107). As a result of the comparison by the determination unit 23, if they do not match, the image projection unit 24 turns off the power of the display device 2 without allowing the user to use, and ends the processing.

  If they match in the process of step 107, then the acceleration sensor unit 21 measures the tilt of the display device 2 (step 108). Next, the determination unit 23 compares the inclination measured by the acceleration sensor unit 21 with the inclination stored in the storage unit 22 (step 109). As a result of the comparison by the determination unit 23, if they match, the image projection unit 24 permits the user to use and starts projecting an image (step 110). As a result of the comparison by the determination unit 23, if they do not match, the image projection unit 24 turns off the power of the display device 2 without allowing the user to use, and ends the processing.

  As described above, according to the present embodiment, the display device 2 stores the set values of the projection distance and the tilt in advance, measures the projection distance and the tilt when the power is turned on, and the projection distance. If the measured value of the inclination and the measured value coincide with the set value, the user is permitted to use and the projection onto the screen 1 is started. This allows the user to use the display device without having to enter passwords or insert keys, or to remove the anti-theft mode before lifting or pay attention to it. Since the display device can be used by returning to the state, the troublesomeness of the user's work and attention associated with theft prevention is reduced.

  In the present embodiment, the example in which the display device 2 includes both the distance sensor unit 20 and the acceleration sensor unit 21 is shown, but the present invention is not limited to this. For example, the display device may include only one of the distance sensor unit 20 and the acceleration sensor unit 21. When the distance sensor unit 20 is provided, the display device 2 measures the measured projection distance with the distance sensor unit 20 when the power is turned on. If the measured projection distance matches the stored projection distance, the display device 2 permits use by the user. To do. When the acceleration sensor unit 21 is provided, the display device 2 measures the tilt with the acceleration sensor unit 21 when the power is turned on, and permits the user to use the measured tilt if the stored tilt matches. According to this, the structure of the display device can be simplified, and the troublesomeness of paying the user's work and attention for preventing theft can be reduced.

It is a schematic diagram which shows the installation state of the display system provided with the antitheft function in this embodiment. It is a block diagram which shows the structure of the display apparatus 2 in this embodiment. It is a figure which shows an example of the acceleration measured by the acceleration sensor part 21 in this embodiment. It is a flowchart which shows operation | movement of the display apparatus 2 provided with the anti-theft function in this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Screen 2 Display apparatus 20 Distance sensor part 21 Acceleration sensor part 22 Memory | storage part 23 Judgment part 24 Image projection part 100-110 step

Claims (10)

A display device that projects an image on a projection surface,
A storage unit for storing the first distance;
When the power is turned on, a distance sensor unit that measures the distance to the projection surface;
A determination unit that determines whether or not a distance measured by the distance sensor unit matches the first distance;
If the result of the determination by the determination unit indicates that they match, the image can be projected onto the projection surface, and if it does not match, the image is projected onto the projection surface. An image projection unit that is not allowed to be displayed. A display device that projects an image on a projection surface,
A storage unit for storing the first inclination;
When the power is turned on, an angle sensor unit that measures the tilt of its own device,
A determination unit that determines whether or not the inclination measured by the angle sensor unit matches the first inclination;
If the result of the determination by the determination unit indicates that they match, the image can be projected onto the projection surface, and if it does not match, the image is projected onto the projection surface. An image projection unit that is not allowed to be displayed. A display device that projects an image on a projection surface,
A storage unit for storing the first distance and the first inclination;
When the power is turned on, a distance sensor unit that measures the distance to the projection surface;
When the power is turned on, an angle sensor unit that measures the tilt of its own device,
It is determined whether or not the distance measured by the distance sensor unit matches the first distance, and it is determined whether or not the tilt measured by the angle sensor unit matches the first tilt. A determination unit;
If the result determined by the determination unit indicates that both match, the image can be projected onto the projection surface, and if either indicates that they do not match, An image projection unit that does not project an image.   The distance sensor unit measures the time required from irradiation to light reception when irradiating the projection surface with light and receiving reflected light from the projection surface, and measures the distance based on the measured time. The display device according to claim 1 or 3.   The angle sensor unit can detect a component value obtained by decomposing gravitational acceleration in a predetermined direction, and when the component value is detected, the inclination is measured based on the detected component value. The display device described. A theft suppression method for suppressing theft of a display device that projects an image on a projection surface,
Remembers the first distance,
When the power is turned on, measure the distance to the projection surface,
If the measured distance matches the first distance, the display device is put into a state where an image can be projected onto the projection surface. If not, the display device is projected onto the projection surface. Do not do, theft control method. A theft suppression method for suppressing theft of a display device that projects an image on a projection surface,
Remembers the first slope,
When the power is turned on, measure the tilt of the display device,
If the measured tilt matches the first tilt, the display device is put into a state where an image can be projected onto the projection surface. If not, the display device is projected onto the projection surface. Do not do, theft control method. A theft suppression method for suppressing theft of a display device that projects an image on a projection surface,
Remembers the first distance and the first slope;
When the power is turned on, measure the distance to the projection surface and the tilt of the display device,
Determining whether the measured distance matches the first distance and determining whether the measured slope matches the first slope;
If the determined results match, the display device is put into a state where an image can be projected onto the projection surface. If either one does not match, the display device projects an image onto the projection surface. No anti-theft method.   The display device measures a time required from irradiation to light reception when irradiating the projection surface with light and receiving reflected light from the projection surface, and measures the distance based on the measured time. Item 9. The antitheft method according to item 6 or 8.   The said display apparatus can detect the component value which decomposed | disassembled the gravitational acceleration in the predetermined | prescribed direction, and if this component value is detected, the said inclination will be measured based on this detected component value. Theft suppression method.

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